Normally, when the mitral or tricuspid valves close, the valve prevents the escape of blood through the annulus. The operation of these valves (plus the normal closure of the aortic and pulmonary valves) ensures that the heart functions as a one-way pump. Pressure within the ventricles forces the leaflets upward until the free edges contact (coaptation). The leaflets are also inhibited by the chordae tendinae from prolapsing beyond the plane of the annulus and into the atrial chambers.
There are many possible causes for failure of these valves, including: loss of pliability of the annulus leading to decreased contractibility; widening of the annulus; thickening, shortening or swelling of the leaflets; dilation of the ventricle; elongation or breaking of the chordae tendinae; and elongation of the attachment of the chordae tendinae with the papillary muscles or ventricular wall. Failure may eventually lead to loss of coaptation of the leaflets, loss of competence of the valve and decreased efficiency of the heart as a one-way pumping mechanism. When the latter occurs, various symptoms are seen in the patients, including breathlessness or lack of stamina and heart murmurs.
Typical treatment of heart valve stenosis or regurgitation, such as mitral or tricuspid regurgitation, involves an open-heart surgical procedure to replace or repair the valve. Currently accepted treatments of the mitral and tricuspid valves include: valvuloplasty, in which the affected leaflets are remodeled to perform normally; repair of the chordae tendinae and/or papillary muscle attachments; and surgical insertion of an “annuloplasty” ring. This requires suturing a flexible support ring over the annulus to constrict the radial dimension. Other surgical techniques to treat heart valve dysfunction involve fastening (or stapling) the valve leaflets to each other or to other regions of the valve annulus to improve valve function (see, e.g., U.S. Pat. No. 6,575,971).
Unfortunately, each of the methods described above has disadvantages which limit the applicability and usefulness of these techniques. For example, many of these treatments inhibit the motion of the valve flaps during normal cardiac function. Most annuloplasty rings inhibit the full range of motion for normal valves, because of the presence of the bulky and constrictive annuloplasty ring. Further, many of the techniques used to treat valve dysfunction rely upon the continued function of the implant (e.g., annuloplasty ring, staples, etc.) to maintain the shape and function of the heart valve. Thus, if the implant fails, the valve will likely fail. Finally, many of the currently available techniques must be performed as part of an open-heart surgery, and cannot be readily practiced non-invasively (e.g., percutaneously) on a beating heart. Open-heart procedures typically involve greater risk, associated pain, and recovery time.
Thus, it would be highly beneficial to provide methods, devices, and systems for enhancing heart valve repair. Ideally, such methods, devices and systems would overcome many of the limitations described above.